1. Field
Exemplary embodiments relate to systems and methods for reducing, and preferably preventing, the contamination of devices and/or surfaces, such as, for example, image forming members, by corona generating devices.
2. Description of Related Art
Corona generating devices include, for example, corona generating wires or corona generating pins which when subjected to a high voltage create an electric field. The strong electric field around the corona generating wires and/or pins causes air to breakdown and cause charges (electrons and/or ions) to flow to another member and/or surface. When a high voltage is applied to the corona generating device and an electric field is formed, undesirable contaminants (such as ozone, NOx, etc.) usually form. The charged corona generating devices also cause corona winds (air flow) to form in the vicinity of the corona generating member, such as, the corona generating wire or the corona generating pin. The formed corona winds may include air streams which flow toward and reach, for example, a surface to be charged. The formed corona winds may also carry other undesirable particles, such as dust, which exist in the vicinity of the corona generating member and/or the corona generating device and/or along the path of the air stream, to that surface. Depending on the type of device employing the corona generating device and/or the purpose of the corona generating device, the deposit of such undesirable particles may cause problems such as, for example, the deterioration of a surface to be charged.
For example, image forming devices, such as printers, facsimile machines, copiers, etc. may employ corona generating devices to charge a surface of an image forming member, such as a photoreceptor on which a latent image of the image to be printed is formed. Typically, during an image forming process, the surface of the photoreceptor is uniformly charged before being exposed to a light beam which selectively discharges the uniform electrostatic charge on the photoreceptor, based on the image data, to form a latent image from the image data. The photoreceptor may, for example, be uniformly charged via electrical charges generated by an electric field formed by a corona generating device. The latent image is then developed by bringing a developer (e.g., toner) into contact with the formed latent image. The developed image is then transferred to a recording medium, such as, for example, a sheet of paper or plastic. The transferred image is then fixed to the recording medium, for example, by a fuser, and/or subjected to further processing.
Corona generating devices can be employed during various operations performed within the image forming devices. For example, corona generating devices can be used to charge the photoreceptor, to transfer the formed toner image from the photoreceptor to the recording medium and/or to pre-clean the photoreceptor of residual toner that might remain on the photoreceptor after transfer of the toner image to the recording medium, etc.
However, contamination of the member exposed to the corona winds (air flow) and any contaminants carried therewith can cause problems, such as, for example, lateral charge migration (LCM) and photoreceptor cracking. Such problems are even more pronounced in an VOC-contaminated environment (VOC, volatile organic compounds) and/or in devices, such as image forming devices, which employ multiple corona generating devices. That is, the more corona generating devices provided in the image forming device, the more undesirable particles will be deposited on the photoreceptor, for example.
It is known for image forming devices to employ an air flow management mechanism to reduce ozone and dirt contamination of the surface to be charged. For example, U.S. Pat. No. 6,397,024 discloses the use of deflector plates to divert contaminated air flow streams away from the corona charger. However, while such conventional air flow management mechanisms may reduce ozone emission and dirt deposits on the surface to be charged, they do not prevent and/or substantially reduce corona effluents from contaminating the surface to be charged.
U.S. Pat. No. 6,678,486 discloses a contamination control apparatus which uses an input air port and an output air port to produce an air current for removing contaminants from the area near the corona generating device. FIG. 8 illustrates the contamination control apparatus, which has a push duct 201, which creates a high velocity air stream that reduces the number of effluents 205 which breach into the air curtain 215. The effluents 205 are removed from the area near the corona generating device by a pull duct 202. As shown in FIG. 8, the push duct 201 and the pull duct 202 are situated along the sidewalls of the corona charger 2 such that the air that is input via the push duct 201 exits with effluents via the pull duct 202 situated across from it along the other side wall of the corona charger 2.
The contamination control apparatus 2 employed in U.S. Pat. No. 6,678,486 requires the use of a push duct 201 and a pull duct 202 to generate an air current 215, which increases the cost and size of the corona generating device. In addition, the push duct and the pull duct must be placed along the side wall, and more particularly, along the end of the side wall of the corona generating device, as shown in FIG. 8. Thus, the size of the corona generating device in the process direction (i.e., along the direction of motion of the photoreceptor) is increased by at least the length of the push and pull ducts along that direction. In devices employing multiple corona devices in series, for example, the overall size the device occupies along the process direction and the cost of the device may be substantially increased and the area of the device assembly exposed to the photoreceptor is not used efficiently because of the push ducts and pull ducts in the side walls of the corona generating devices.
To satisfy the demand for smaller and lower-cost devices, it is desirable to provide a contamination reducing system and method which is smaller in size and cheaper and easier to implement and operate.